IRRIGATION' IN FLOEIDA, 35 



to 300 acres in the western part of the State, the largest acreage 

 being in Polk and Hillsboro Counties. 



Spra t y irrigation has been found to be of considerable value as a 

 protection against frost in the southern part of the State. Some 

 farmers claim they have saved their entire crop from frost injury by 

 their spray systems. 



The installation of a complete irrigation system covering several 

 acres by means of these nozzles does not differ greatly from that of 

 the overhead-pipe system, the pumping outfit and main line being 

 similar in both. The lateral lines of the overhead-pipe system must 

 be elevated above the ground surface, as every nozzle is turned on at 

 once. The laterals of the other systems usually are placed under- 

 ground, while the nozzles are elevated by means of upright pipes 

 connected to the underground lines. In the overhead-pipe system 

 the lateral lines are placed perpendicular to the main, the size of 

 the pipe increasing toward the main as the length of the lateral 

 line is increased. The circular nozzles are placed close enough 

 together so that water from one will overlap the space watered by its 

 neighbor. The parallel laterals also must be placed close enough to- 

 gether for the irrigated spaces to meet. It is evident that this dis- 

 tance will vary with the radius of distribution of the nozzle. The 

 nozzles of alternate laterals usually are placed opposite, so that the 

 circular areas covered by all the nozzles will fit into each other. 



It is not necessary to go into details of the design of pump and 

 engine, as it will be seen that if the capacity of each nozzle is known 

 the problem differs in no way from that of the overhead-pipe 

 systems. The stationary-nozzle types usually require considerably 

 more water than the other system, and this means larger pipe lines if 

 the same amount of land is to be irrigated at one time. Each lateral 

 is fitted with a cut-off, as in the case of the overhead-pipe system, so 

 that any amount of land required may be watered simultaneously, 

 provided the main and the pumping outfit are of proper size and ca- 

 pacity. The pressure required is about the same for all the overhead 

 systems. 



Advocates of the whirling-nozzle type claim that their systems are 

 automatic and need no turning by hand. The advocates of over- 

 head-pipe systems claim that this difficulty can be overcome easily by 

 installing an automatic turning machine, and that the turning of the 

 lines by hand is very simple and requires little time away from other 

 work. The small aperture in the overhead-pipe nozzle may cause 

 trouble by becoming clogged with small pieces of sand or fiber. This 

 docs not happen usually with some rotation nozzles, but may stop 

 others. Good screens or filters will stop this trouble to a large extent. 

 The smaller nozzle may be cleaned with a pin and the rotating nozzles 



